Russian troops are carrying out an intensive search for Chechen fighters in several towns in the breakaway region. Both sides in the long-running conflict claim to have inflicted heavy losses on the other.

Russian military officials say troops are conducting a massive sweep through a wide area of Chechnya. Soldiers have surrounded the town of Argun, where the military says some key rebel leaders may be hiding. Dozens of roads have been blocked in an attempt to prevent fighters from leaving the area, south of the capital, Grozny.

Military officials say scores of rebel fighters have been killed in recent days, although casualty figures are impossible to verify independently. The Chechens claim to have killed many Russian soldiers. The rebels' website also says Russian troops killed civilians and looted property in a village not far from Argun. Heavy fighting has been going on for at least a week in the village of Tsatsan-Yurt, where Russia claims many fighters are based.

Russian troops invaded the breakaway province in October 1999 in what President Vladimir Putin has long described as a fight against terrorism. The Chechens say they are fighting for independence from Moscow after centuries of repression. They also fought a war from 1994 to 1996, which ended with an inconclusive peace agreement.

Human-rights groups have long accused both sides of committing abuses against non-combatants. Russian troops have come under particular scrutiny for their treatment of Chechen civilians. This has led to pressure on President Putin to seek an end to the conflict through negotiations. Yet the fighting continues, despite a meeting between officials from both sides in November.